The present invention relates to an assembly for inserting an attachment coil in concrete and a method for installing such a coil.
Seating of coils in holes of concrete or masonry members to provide threads for attaching screws or the like is well know. However, prior assemblies and methods for such use have suffered from the difficulty of controlling the location of the seating of the coil selectively to provide optimum strength. Examples of prior apparatus and methods are disclosed in U.S. Pat. Nos. 4,536,115 and 4,635,337 of the present inventor. These prior patents disclose the use of indicia grooves in attachment screws to provide a visually observable indication of when a coil carried on the screw has been inserted in the hole to a desirable depth, but this requires a special and relatively expensive screw with the groove formed therein rather than being able to use an inexpensive conventional screw and does not provide for seating two or more coils at different depths in a hole. Furthermore, when anchoring a fixture or machine to concrete or other masonry the installer is often in an awkward, uncomfortable position, and available lighting may make it difficult to sight a mark or indicia on the shank of the screw.